Examples of a display device are a cathode ray tube (CRT), a liquid crystal display (LCD) using an electro-optic effect, a plasma display panel (PDP) using a gas discharge effect, and an electro luminescence displays (ELD) using an electro-luminescent effect. Among them, research on the LCD apparatus is conducted more actively.
The LCD apparatus is a light receiving device that adjusts an amount of light transmitted from the outside in order to display an image, and also requires an additional external light source such as a backlight unit.
The backlight unit utilizes a light emitting lamp such as a cold cathode florescent lamp (CCFL), and a light emitting diode (LED).